Portion of a keyboard



FIG. 1 is a top plan view of a portion of a keyboard showing our new design;

FIG. 2 is a rear view thereof;

FIG. 3 is a front view thereof;

FIG. 4 is left side view thereof;

FIG. 5 is right side view thereof; and,

FIG. 6 is a top perspective view thereof.

The broken line showing of the keys on the top face of the keyboard and of the bottom of the keyboard is for illustrative purposes only. The uneven broken lines immediately adjacent the shaded areas represent the bounds of the claimed design. The even and uneven broken lines form no part of the claimed design. The unshaded regions including the keys and bottom of the keyboard form no part of the claimed design. 

The ornamental design for a portion of a keyboard, as shown and described. 